Electric motor vehicle for transport of goods made of a rotomoulded body supported by a modular tubular frame

ABSTRACT

An electrically powered motor vehicle for transport of goods, of the minivan type, includes a main frame, a front axle assembly and a rear axle assembly. The main frame includes a front frame subassembly, a floor-panel subassembly, a rear frame subassembly, and a top frame subassembly. Each of these frame subassemblies includes a lattice structure including box-section elements made of steel, preferably high-strength steel. Each of the frame subassemblies is prearranged for being preassembled separately and subsequently assembled together with the other subassemblies so as to constitute the main frame. The structure is such as to afford high flexibility of production, and presents at the same time considerable safety characteristics, thanks to a high capacity of absorption of impact energy. The motor vehicle is equipped with a transporting body having a hollow-walled body made of plastic material, filled with foamed plastic material, preferably obtained with the rotational-molding technique.

FIELD OF THE INVENTION

The present invention relates to the field of electrically powered motorvehicles, with particular reference to the category of minivans fortransport of goods.

Even more in particular, the invention regards an electrically poweredmotor vehicle, of the type comprising:

-   -   a main frame;    -   a front axle assembly; and    -   a rear axle assembly,    -   wherein said axle assemblies each comprise an auxiliary        supporting frame and two suspension units that connect two        respective wheel supports to said auxiliary supporting frame,        and    -   wherein at least one of said axle assemblies is a motor-driven        axle with steering wheels, further comprising, mounted on said        auxiliary supporting frame, an electric motor for driving the        wheels in rotation, a control unit of said motor, a transmission        unit for transmission of motion 20 from the electric motor to        the wheels, and a steering device for enabling steering of the        wheel supports.

OBJECT OF THE INVENTION

A first object of the present invention is to provide the motor vehiclewith a container body for transport of goods that presents at the sametime good characteristics of sturdiness and lightness and is configuredfor being integrated with simple operations in the structure of themotor vehicle.

A further object is to provide a motor vehicle, the structuralarchitecture of which will enable drastic simplification ofmanufacturing processes and equipment, consequently reducing theinstallation costs, so as to render even a small-scale productioneconomically advantageous.

A further important object of the present invention is to provide amotor vehicle with a structural architecture that will afford highflexibility of production in the sense of enabling production of variousversions or models of motor vehicle through simple and economicallyadvantageous adaptations of the production equipment.

A further object of the invention is to achieve all the aforesaidtargets with a motor-vehicle structure that will guaranteecharacteristics of sturdiness and safety for the occupants in the eventof impact that are considerably superior to the ones that can normallybe obtained in motor vehicles of the same category.

A further object of the invention lies in the creation of amotor-vehicle structure that will guarantee an efficient housing spacethat is protected from impact for the electrical batteries for supplyingthe electric drive motor or motors provided on board the motor vehicle.

Finally, a further object of the invention is to provide a motor-vehiclestructure that can be assembled with extremely simple operations and inextremely short production times.

SUMMARY OF THE INVENTION

With a view to achieving all the aforesaid objects, the subject of thepresent invention is a vehicle having all the characteristics of theannexed claim 1.

Further preferred and advantageous characteristics of the motor vehicleaccording to the invention are specified in the annexed dependentclaims.

Thanks to the above characteristics, the present invention achieves aseries of important advantages.

First of all, division of the structure of the main frame intosubassemblies, and the specific configuration described in what followsof each of these subassemblies enables a drastic simplification in theoperations of manufacture and assembly, together with an extremely highflexibility of production given that the aforesaid structure is suitedfor production of a large number of different versions and models ofmotor vehicle with simple and immediate adaptations of the structure andof the corresponding production equipment.

The use of lattice structures with arms constituted by box-sectionelements made of sheet steel, preferably high-strength steel, at thesame time enables extremely good characteristics of sturdiness andsufficiently low production costs to be obtained, thus allowing evenmedium-scale and small-scale production. The specific structuredescribed in what follows of the front and rear frame subassemblies andin particular the provision of front struts for absorption of impactenergy on two levels set on top of one another and at a distance apart,distributed along the width of the structure, enables a very highcapacity of absorption of impact energy to be obtained for motorvehicles of this category.

Use of rotational-moulding technology to produce the container body forthe transport of goods proves extremely advantageous in so far as itenables elements to be obtained with the necessary qualities ofsturdiness and at the same time good characteristics of lightness.Rotational-moulding technology is on the other hand perfectly compatiblewith the production of motor vehicles of this category, above all in thecase of medium- or small-scale production. The transporting body has astructure that enables its production with extremely simple and low-costoperations. The same applies to the operations necessary for adaptingthe frame of the motor vehicle to receive the aforesaid transportingbody, which once again demonstrates the extreme flexibility and economyof production that are afforded by the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to theannexed drawings, which are provided purely by way of non-limitingexample and wherein:

FIG. 1 is a perspective view of a first model of an electric car thatdoes not form part of the present invention, but the description ofwhich is useful for the purposes of an understanding of the presentinvention;

FIG. 2 is a perspective view of the main frame of the car of FIG. 1;

FIG. 2A is a perspective view of the two front and rear axle assembliesthat form part of the car of FIG. 1 and are provided with respectiveauxiliary supporting frames designed to be assembled on the frame ofFIG. 2;

FIG. 3 is an exploded perspective view of the frame of FIG. 2;

FIG. 3A is a perspective view from beneath of the front framesubassembly forming part of the frame of FIGS. 2 and 3;

FIGS. 4 and 5 are further perspective views of the frame of FIG. 2completed with two different versions of the front cross member and ofthe rear cross member;

FIG. 6 is an exploded perspective view, which shows the frame of FIG. 2together with the auxiliary supporting frames for the axle assemblies,for a first version of the front and rear suspensions of the motorvehicle;

FIG. 7 is a view from beneath of the same elements as those illustratedin FIG. 6, which shows the points of connection of the auxiliary framesto the main frame;

FIG. 8 illustrates a variant of FIG. 6, corresponding to a differenttype of front and rear suspensions;

FIG. 9 illustrates a first solution for housing the electrical supplybatteries, in exploded view;

FIG. 10 is a partial cross-sectional view, in a transverse plane, of theassembly of FIG. 9;

FIG. 11 is a further exploded perspective view that shows a differentsolution for housing the electrical supply batteries;

FIG. 12 is a perspective view of a model of motor vehicle according tothe invention, of the minivan type, for transport of goods;

FIG. 13 is a perspective view of the main frame of the motor vehicle ofFIG. 12;

FIG. 14 shows the frame of FIG. 13 completed with the container bodyprearranged for transport of goods;

FIG. 15 is an exploded perspective view that illustrates the sameelements as those of FIG. 14;

FIG. 16 is an exploded perspective view only of the assembly of thevarious elements constituting the body of the container;

FIG. 17 is a side view of the frame of the motor vehicle with the bodyof the container;

FIGS. 18 and 19 are cross-sectional views at an enlarged scale of thedetails XVIII and XIX of FIG. 17;

FIGS. 20 and 21 are a front perspective view and a rear perspective viewof a bumper that can be used both as front bumper and as rear bumper ofthe motor vehicle according to the invention;

FIG. 22 is a cross-sectional view at an enlarged scale of the bumper ofFIGS. 20 and 21;

FIG. 23 illustrates at an enlarged scale the detail XXIII of FIG. 22;and

FIGS. 24-31 refer to a variant of the first embodiment of the invention,wherein:

FIG. 24 is a variant of FIG. 2,

FIG. 25 is a variant of FIG. 3,

FIG. 26 shows the structure of FIG. 24, completed with some elementsmade of sheet metal,

FIG. 27 is a variant of FIG. 2A,

FIGS. 28 and 29 illustrate the corresponding variants of FIGS. 6 and 7,

FIGS. 30 and 31 illustrate the corresponding variant of FIG. 5, in theassembled condition and in exploded view, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Designated by 1 in FIG. 1 is an electric car of the city-car categorythat has in common a series of features with the motor vehicle formingthe subject of the present invention. Its description is hence usefulfor the purposes of a better understanding of the invention.

In the specific example illustrated, the car 1 is a car with a singlecentral driving seat and two rear seats, which can be obtained accordingto different versions or configurations. In one version, there areprovided only one front door 2 and one rear door 3 on one and the sameside of the vehicle (which may indifferently be the left side or theright side for countries with right-hand driving and left-hand driving).In this version of the car, the structure of the motor vehicle iswithout the upright B on the side of the doors. The front door 2 ishinged at the front, and the rear door 3 is hinged at the rear, so thatthe two doors 2, 3 open like a book leaving access to the driving seatand to the two rear seats completely free. Otherwise, the car may beprovided with just two conventional front doors on the two sides of thecar, in which case the uprights B are provided on both sides of theframework. Provided on the roof panel are photovoltaic cells 200 inthemselves of a known type, englobed in a sheet made of flexible plasticmaterial glued to the roof panel.

FIG. 2 shows an example of embodiment of the frame of the motor vehicleof FIG. 1, in the version with uprights B on both sides (whilst FIGS.4-8 show the version without one of the two uprights B). The frameillustrated in FIG. 2, and designated as a whole by the reference number4, constitutes the main frame of the motor vehicle, designed to receivetwo auxiliary frames 5 (see FIG. 2A) for supporting front and rear axleassemblies 6, 7.

The example illustrated in FIG. 2A regards the solution that has alreadyformed the subject of the prior Italian patent application No.TO2014A000305, filed in the name of the present applicant, where eachaxle assembly comprises two suspension units 8 that connect therespective wheel supports to the auxiliary supporting frame 5, anelectric motor M for driving the wheels in rotation, a control unit Efor the electric motor M, and a transmission assembly 9 withdifferential for transmission of motion from the electric motor to thewheels. Furthermore, once again in the case of the specific exampleillustrated, both of the front and rear axle assemblies have steeringwheels and consequently include a steering device 10 for control ofsteering of the wheels. It is, however, to be emphasized that theinvention discussed herein applies also to a motor vehicle in which theelectric motor M, the corresponding control unit E, the transmissionunit 9, and the steering device 10 are associated only to one of the twoaxle assemblies, the other axle assembly carrying only the tworespective suspension units 8.

In the aforesaid embodiment, each wheel is rotatably mounted on a wheelsupport (not visible in the drawings), which is mounted oscillating onthe respective supporting frame 5 by means of a top transverse arm 51and a bottom transverse arm 52. Each transverse arm has a triangularconfiguration, with one end connected in an articulated way to the frame5 by elastic supporting means and the opposite end connected in anarticulated way to the wheel support. Also associated to each wheel is acylinder/helical-spring shock-absorber assembly, designated as a wholeby the reference 53. Each cylinder/spring shock-absorber assembly isconnected to the bottom arm 52, on each side of each axle assembly. Inthe case of the rear axle assembly, this enables the top end of eachcylinder/spring shock-absorber assembly 53 to be located at a relativelylow level, which enables an increase in the space available in thepassenger compartment of the motor vehicle, in a vertical direction.

A further advantageous characteristic of the embodiment that isillustrated herein lies in the fact that the top arms 51 of the rearaxle assembly have a configuration such that the end of each armconnected to the respective frame 5 is shifted longitudinally withrespect to the outer end of the arm 51 that is connected to therespective wheel support. This result is achieved with an arm 51 havinga markedly curved configuration in plan view. In the case of the rearaxle assembly, the outer end of each arm 51 is shifted longitudinallyforwards, whereas in the case of the front axle assembly the outer endof each arm 51 is shifted longitudinally backwards. Thanks to thisconfiguration, the cylinder/spring shock-absorber assembly 53 associatedto each rear transverse arm 51 can be positioned in such a way as toleave free the space within the passenger compartment in the area of thetwo rear lateral seats of the motor vehicle. Consequently, thanks tothis configuration of the rear axle assembly, the rear lateral seats ofthe motor vehicle according to the invention can be positioned at aconsiderable distance from one another, in the transverse direction, ascompared to the external transverse dimension of the car, whichincreases considerably the space available for the passengers, in thetransverse direction.

In the embodiment illustrated, the two front and rear axle assembliesare identical to one another (except for the fact that one is rotatedthrough 180° with respect to the orientation of the other) so as tosimplify and render more economically advantageous production of thecar.

With reference now to FIGS. 2, 3, and 3A the frame 4 is constituted byframe subassemblies that are preliminarily assembled each individuallyso that they can then be connected together in a fast way. Withreference in particular to FIG. 3, the main frame 4 hence comprises afront frame subassembly 40, a floor-panel subassembly 41, a rearsubassembly 42, and a top subassembly 43.

According to an important characteristic common to the motor vehicle ofthe present invention, each of the above sub-assemblies has a latticestructure including arms constituted by box-section elements made ofsteel, preferably high-strength steel. Studies and experiments conductedby the applicant have in fact shown that use of the above materialenables advantages to be achieved comparable even to those of aluminiumin terms of lightness, at the same time guaranteeing a high level ofsturdiness and simplifying considerably the operations of manufacture,with consequent significant reduction in costs.

With reference now in particular to FIGS. 2 and 3A, the framesubassembly 40 comprises two lateral uprights A connected by a latticestructure projecting at the front from which are four longitudinalstruts 401 for absorbing impact energy, set at a first, top, level anddistributed in the transverse direction over the width of the frame, andtwo longitudinal struts 402, which are also designed for absorbing theimpact energy and are set at a second, bottom, level, symmetrically atthe two sides of the longitudinal median plane of the motor vehicle. Allthe longitudinal struts 401, 402 constitute as many crash boxes, whichare designed to collapse following upon a front impact, for absorbingthe impact energy. The two struts 401 located more adjacent to themedian plane of the motor vehicle are vertically aligned with the struts402. The front ends of the top struts 401 are connected to a crossmember 401 a, designed to distribute the force of impact over thestruts. The two bottom struts 402 have their front ends connected toplates 404 designed to be connected to a cross member altogether similarto the cross member 403 or else to a cross member integrated in a bumperof the motor vehicle, according to what will be described in greaterdetail in what follows. In its top part, the lattice that connects theuprights A further comprises a cross member 405 which has the purpose ofsupporting the steering column, and a further cross member 406constituting the bottom supporting edge for the windscreen of the motorvehicle.

As is evident, the structure of the front subassembly 40 of the frame ofthe motor vehicle according to the invention at the same time presentsgood characteristics of lightness and sturdiness and a great capacity ofabsorption of impact energy that leads the motor vehicle according tothe invention to represent a step forwards as compared to motor vehiclesof the same category built so far.

The floor-panel subassembly 41 comprises two main longitudinal or sidemembers 410 connected together by a pair of front cross members 411, setvertically at a distance apart, and by two pairs of intermediate crossmembers 412, 413, which are also set vertically at a distance apart. Theconnection between the rear ends of the two longitudinal members 410 isinstead completed with assembly of the rear frame subassembly 42. Theframe subassembly 41 is completed with a sheet-metal floor panel 414,set underneath the lattice constituted by the longitudinal members 410and by the cross members 411, 412, 413. The metal sheet 414 is acorrugated metal sheet with longitudinal ribbings oriented in thelongitudinal direction of the motor vehicle. The structure of thelongitudinal members 410 and of the cross members 411, 412, 413 isobtained with the technique of steel box-section elements. Projectingfrom the pair of front cross members 411 are inclined longitudinal arms415, the front ends of which are connected to the lattice constitutingthe front frame subassembly 40.

The structure described above of the floor-panel subassembly 41 isconceived for achieving the necessary characteristics of sturdiness andat the same time providing three containment spaces (one space betweenthe pairs of intermediate cross members 412, 413, and two spaces at thefront and at the back of these cross members) designed for housing theelectrical batteries for supplying the motor vehicle, as will bedescribed in greater detail in what follows. Two further longitudinalmembers 416 extend longitudinally within the two main longitudinalmembers 410, for connecting together the bottom cross members of thepairs 411, 412, 413 and the front cross members forming part of the rearframe subassembly 42.

With reference now to FIGS. 2 and 3, also the rear frame subassembly 42comprises a lattice structure constituted by box-section arms made ofsteel. This structure includes a pair of front cross members 421 setvertically at a distance apart from one another, which connect togetherthe rear ends of the longitudinal members 410 and 416. The latticeincludes two longitudinal struts 422, which terminate with plates 423designed to be connected by a cross member (in the way that will bedescribed in detail in what follows) for absorbing rear impact. Thelattice of the rear subassembly 42 further includes lateral arms 423,the rear ends of which are connected together by a cross member 424 andare moreover designed to be connected to the bottom ends of the uprightsC, which form part of the top frame subassembly 43. The lateral arms 423extend vertically higher up than the longitudinal struts 422 and thanthree cross members 425 that connect together the struts 422 in such away that these cross members 422 define a resting surface for the rearseat of the motor vehicle.

With reference once again to FIGS. 2 and 3, the top subassembly 43 hastwo longitudinal members 430 that with their front portions 430 a definethe side edges of the supporting frame for the windscreen. The mainportions of the longitudinal members 430 define, instead, thelongitudinal supporting elements of the roof panel, connected togetherby cross members 431. Pre-assembled on the longitudinal members 430 arethe top ends of the uprights B and C in such a way that the operationsfor assembly of the frame 4 proceed after the four subassemblies 40, 41,42, 43 have been preliminarily assembled according to the configurationsillustrated in FIG. 3. The aforesaid subassemblies are then completedwith front elements made of sheet metal 440, 441, 442 so as toconstitute the firewall that separates the passenger compartment of thecar from the front axle assembly, sheet-metal plates 450, 451 thatseparate the passenger compartment of the car from the rear axleassembly, and a sheet-metal plate 460 that rests on the cross members425 of the rear frame subassembly so as to constitute the restingsurface of the rear seat.

FIG. 4 shows the example of solution where one and the same type ofcross member 11 is used for connecting together the plates 404 at thefront ends of the struts 402 and the plates 423 at the rear ends of thestruts 422. The cross member 11 is provided at the rear with two crashboxes 110 with flanges for attachment to the plates 404 and 423.

FIG. 5 shows the example of solution where the cross member forconnecting the plates 404 and 423 is englobed in a bumper made ofplastic material 12.

FIGS. 20-23 of the annexed drawings refer to a preferred example ofembodiment of the bumper 12 that envisages use of the technique ofrotational moulding for producing the bumper. In this way, it ispossible to obtain a hollow structure having a wall made of rigidplastic material, for example polyethylene, with the internal cavitythat is subsequently filled with foamed plastic material, for examplepolyurethane, for bestowing the necessary characteristics of sturdiness.With reference to the example of FIGS. 20-23, the bumper 12 has a hollowpolyethylene body 120, having walls 121 and an internal cavity 122(filled with polyurethane). The body 120 is shaped with two rearprojections 123, embedded in which are steel plates 124 with threadedbushings 125 for enabling screwing onto the brackets 404, 423. Theserear projections 123 have the dual purpose of enabling convenientengagement of the bumper to the main frame and absorbing all the energyof an impact at a speed lower than 16 km/h in such a way that thedeformation will not be transferred to the rest of the frame, thuslimiting damage due to impact (so-called “assurrance test”).

Once again with reference to the example of embodiment of FIGS. 20-23,the front surface of the bumper 12 has a shaped step 126 where a groove127 is formed in which a bottom edge of a front panel of bodywork 128engages (see FIG. 23). The groove 127 has a depth such as to ensure acertain play for the bottom edge of the panel 128 inside it, whichenables relative movements between the panel of the body and the bumper12.

With reference now to FIGS. 6 and 7, illustrated therein are the mainframe of the motor vehicle 4 already described above, together with thetwo auxiliary supporting frames 5 in the version of the frames 5prearranged for suspensions of the articulated-quadrilateral type.

As may be seen in FIG. 7, each of the frames 5 is assembled on the mainframe 4 by being bolted only at four fixing points (F1 on the frame 4and F2 on the auxiliary frame 5).

FIG. 8 shows a variant in which the auxiliary frames 5 are prearrangedfor carrying suspensions of the McPherson type, the entire suspensionunit being pre-assemblable on the frame 5 and mountable therewith in asubsequent step on the frame 4. FIG. 8 also regards an example in whichthe left upright B is eliminated to enable provision on the left side ofthe car of two doors that open in booklike fashion and enablefacilitated access to the front and rear seats.

FIGS. 9 and 11 show two alternative solutions for prearrangement of theelectrical batteries for supplying the motor or motors located on boardthe motor vehicle. These figures show the advantage of the structurealready described above, which is prearranged for the floor-panelsubassembly 41. In the solution of FIG. 9, two containers of batterymodules are provided in the areas set at the front and at the back,respectively, of the two pairs of intermediate cross members 412, 413.FIG. 11 shows a solution in which a single container is provided in thearea comprised between these cross members.

In FIG. 9, each of the two battery-module holder units comprises abottom container 130 made of electrically insulating material (see alsothe cross-sectional view of FIG. 10) set within which is a bottom steelcontainer 131 provided on its edge with a seal gasket 132. Set withinthe container 131 are a series of battery modules 133, located abovewhich is a plate made of insulating material 134 that is then covered bya lid 135, the edge of which co-operates with the seal gasket 132. Thesame structure described above is adopted also in the case of thesolution of FIG. 11, which envisages a single container in the centralspace comprised between the cross members 412, 413.

FIGS. 12-19 show a preferred embodiment of a motor vehicle of theminivan category according to the invention.

In this case, the motor vehicle has two front doors 2, or even just onefront door, and is equipped at the rear with a container body 14 fortransport of goods.

FIG. 13 shows the frame 4 of the motor vehicle of FIG. 12. As may beseen, the frame is substantially identical to the version illustrated inFIGS. 2 and 3, except for the fact that the top frame subassembly 43 iswithout all the part that extends behind the uprights B.

FIG. 14 shows the transporting body 14 assembled on the frame 4. In thiscase, the assembly operations are identical to those already describedabove with reference to the motor vehicle of FIG. 1, except for the factthat, after the frame subassemblies 40, 41, 42, 43 have been assembledto form the frame 4, the transporting body 14 is installed by beingbolted on the frame 4 itself.

As may be seen in FIGS. 15, 16, the transporting body 14 is constituted,in the example illustrated, by a bottom element 140, a top element 141,and a door 142 for access to a door compartment defined on one side ofthe body constituted by the two bottom and top elements 140, 141.

In a variant, it would be possible to provide only the bottom element ofthe transporting body 140 so as to create a version of motor vehicle ofthe pick-up type.

According to a preferred characteristic of the present invention, thebody of the elements of the transporting body 140, 141 is made ofplastic material and is obtained with the rotational-moulding technique,in such a way as to define, for each of these elements, a hollow bodywith a wall made of rigid plastic material 143, for examplepolyethylene, and a cavity 144 filled with foamed plastic material, forexample polyurethane or aerogel (see FIGS. 18 and 19).

As may be seen in the detail of FIGS. 18 and 19, the bottom and topelements 140,141 have mutually engaging edges defining alabyrinthine-profile configuration, with an S-shaped profile to preventany leakage of water into the transporting body 14. Moreover providedare attachment points for mutual connection of the elements 140, 141 atwhich embedded in the polyethylene wall 143 of the two elements 140, 141are metal brackets 145 and threaded bushings 146 for connection usingscrews 147 (see FIGS. 18 and 19).

From the foregoing description it is evident that the invention achievesa series of important advantages.

First of all, the division into the subassemblies described above of thestructure of the main frame 4 and the specific configuration describedabove of each of these subassemblies enables drastic simplification inthe operations of manufacture and assembly together with an extremelyhigh flexibility of production given that the aforesaid structure issuited for production of a large number of different versions and modelsof motor vehicle with simple and immediate adaptations of the structureand of the corresponding production equipment.

The use of lattice structures with arms constituted by box-sectionelements made of sheet steel, preferably high-strength steel, at thesame time enables extremely good characteristics of sturdiness andsufficiently low production costs to be obtained, thus allowing evensmall-scale production. The specific structure described above of thefront and rear frame subassemblies and in particular the provision ofthe struts 401, 402 arranged on two levels set on top of one another andat a distance apart, distributed along the width of the structure,enables a very high capacity of absorption of impact energy to beobtained for motor vehicles of this category.

Use of rotational-moulding technology (in the example of embodiment thatmakes use of a front bumper and rear bumper that englobe the crossmember for connecting the struts designed for energy absorption, as wellas in the example of embodiment that envisages use of a container bodyfor transport of goods) proves extremely advantageous in so far as itenables elements to be obtained with the necessary qualities ofsturdiness and at the same time good characteristics of lightness.Rotational-moulding technology is on the other hand perfectly compatiblewith the production of motor vehicles of this category, above all in thecase of medium- or small-scale production.

Of particular importance is the embodiment that envisages use of acontainer body for transport of goods. As has been shown, the aforesaidtransporting body has a structure that enables its production withextremely simple and low-cost operations. The same applies to theoperations necessary for adapting the frame of the motor vehicle toreceive the aforesaid transporting body, which once again demonstratesthe extreme flexibility and economy of production that are afforded bythe present invention. A further important advantage of themotor-vehicle structure described herein lies in the fact that itguarantees efficient and safe housing of the batteries for supplying theelectric motor associated to one or both of the axle assemblies of themotor vehicle.

FIGS. 24-31 refer to a variant of the first embodiment of the invention.In these figures, the parts common to FIGS. 1-11 are designated by thesame references.

The main difference as compared to the first embodiment lies in the factthat in this case the car has a single left front door, for access to acentral driving seat, and a single right rear door, for access to therear seats. This arrangement makes it possible to provide the uprights Bin longitudinally staggered positions, with the right upright B setfurther back and the left upright B set further forward so as to be ableto define door compartments wider than what would be possible if a frontdoor and a rear door were arranged on one and the same side of the car.Of course, the arrangement could be reversed, providing a right frontdoor and a left rear door.

With reference in particular to FIGS. 24-26, the front subassembly 40 issubstantially identical to that of FIG. 2, while the floor-panelsubassembly 41 envisages a single series of cross members 411, 412, 413which connect the two longitudinal members 410 and are designed tosupport a plate (not illustrated) for resting the batteries of the car.The metal sheet 414 in this case is a plane metal sheet. Mounted abovethe frame of the floor panel is a framework 417 (FIG. 25) for supportingthe driving seat, comprising two cross members 418 with their centralportions raised, for supporting a plate of sheet metal (not illustrated)that functions as raised resting surface for the driving seat in such away as to leave the space underneath this surface free, for the feet ofthe passengers sitting in the rear seats. The rear subassembly 42 inthis case has a structure that is not symmetrical with respect to thevertical median plane of the car on account of the asymmetricalarrangement of the side doors. The top subassembly 43 has in this casetwo uprights B that are longitudinally staggered, for the reasonsalready mentioned above, with the left upright B in a position setfurther back with respect to the right upright B. On the right sidewithout front door a beam 432 is provided that extends longitudinallyforwards starting from an intermediate portion of the right upright Band has its front end fixed to the right upright A. Finally, illustratedin FIGS. 24-26 are the left front-door frame DA, provided with hinges H,and the right rear-door frame DP. As has likewise already been said, inthe case of motor vehicles designed for countries with left-handdriving, the structure of the frame of the motor vehicle could bespecularly reversed with respect the one illustrated by swapping aroundthe right-hand parts with the left-hand ones. In general, theintermediate upright B that is set on the side of the rear door is in aposition longitudinally further forward than the intermediate upright Bthat is set on the side of the front door so as to enable doorcompartments of ample dimensions to be obtained.

Of course, without prejudice to the principle of the invention, thedetails of construction and the embodiments may vary widely with respectto what has been described and illustrated herein purely by way ofexample, without thereby departing from the scope of the presentinvention.

The invention claimed is:
 1. An electrically powered motor vehicle fortransport of goods, comprising: a main frame; a front axle assembly; anda rear axle assembly, wherein said axle assemblies each comprise anauxiliary supporting frame and two suspension units that connect tworespective wheel supports to said auxiliary supporting frame, andwherein at least one of said axle assemblies is a motor-driven axle withsteering wheels, further comprising, mounted on the respective auxiliarysupporting frame, an electric motor for driving the wheels in rotation,a control unit of said motor, a transmission unit for transmission ofmotion from the electric motor to the wheels, and a steering device forsteering the wheel supports, wherein said main frame includes: a frontframe subassembly, a floor-panel subassembly, a rear frame subassembly,and a top frame subassembly, wherein each of said frame subassembliescomprises a lattice structure including box-section elements, said framesubassemblies being prearranged for being preassembled separately andsubsequently assembled together to form the main frame, wherein said topframe subassembly is prearranged for incorporating the intermediateuprights of the motor vehicle that upstand from the floor panel assemblybetween the front frame assembly and the rear frame assembly and doesnot include parts that extend behind said intermediate uprights, andwherein fixed to said intermediate uprights and to the rear framesubassembly is a transporting body for transport of goods, thetransporting body comprising at least one tank-shaped bottom elementthat bounds a compartment, the compartment being disposed entirelybehind said intermediate uprights.
 2. The motor vehicle according toclaim 1, wherein the transporting body also comprises a top elementapplied on the bottom element so as to define a container that bounds aninterior space, the container having a door compartment thatcommunicates with the interior space, a door being movably mounted tothe container so that the door can selectively open and close the doorcompartment.
 3. The motor vehicle according to claim 2, wherein thebottom and top elements of the transporting body are made of plasticmaterial and are configured such that each wall of the container has aninternal cavity filled with foamed plastic material.
 4. The motorvehicle according to claim 3, wherein the bottom and top elements of thetransporting body have coupled edges defining engagement surfaces shapedaccording to a labyrinthine profile to prevent any entry of water intothe transporting body.
 5. The motor vehicle according to claim 4,wherein the co-operating edges of said top and bottom elements of thetransporting body have attachment points, embedded in which are metalplates and respective threaded bushings for engagement of connectionscrews.
 6. The motor vehicle according to claim 1, wherein thebox-section elements—are made of steel.
 7. The motor vehicle accordingto claim 2, wherein the top element of the transporting body projectsabove the top frame subassembly.